~~~ import 'package:flutter/material.dart'; void main() => runApp(Myapp()); class Myapp extends StatelessWidget{ @override Widget build(BuildContext context) { // TODO: implement build return MaterialApp( title: 'home', home: Taps(), theme: ThemeData( primarySwatch: Colors.red ), ); } } class Taps extends StatefulWidget{ Taps({Key key}) : super(key:key); _TipsState createState() => _TipsState(); } class _TipsState extends State<Taps>{ int index = 0; @override Widget build(BuildContext context) { // TODO: implement build return Scaffold( appBar: AppBar( title: Text('首页'), ), body: Home(), bottomNavigationBar: BottomNavigationBar( currentIndex: this.index, onTap: (int index){ setState(() { this.index = index; }); }, items: [ BottomNavigationBarItem( icon: Icon(Icons.account_balance), title: Text("首页") ), BottomNavigationBarItem( icon: Icon(Icons.check_box), title: Text("分类") ), BottomNavigationBarItem( icon: Icon(Icons.settings), title: Text("设置"), backgroundColor: Colors.amberAccent ), ], ), ); } } class Home extends StatelessWidget{ @override Widget build(BuildContext context) { // TODO: implement build return Text("你好"); } } ~~~